Toward a theory for low-frequency spin dynamics in plane copper oxide superconductors:crossover from localized spins to weak coupling charge carriers with doping

Abstract

We explore for all wavevectors through the Brillouin zone the dynamic spin susceptibilityχtotal + , − (ω, q) that takes into account the interplay of localized and itinerant charge carriers. The imaginary part,Imχtotal + , − (ω, q), has peaks at the antiferromagnetic wavevectorQ = (π, π) and a diffusive-like, extremely narrow and sharp peak (symmetric ring of maxima|q| = q0) at very small wavevectors with the nuclear magnetic/quadrupole resonance frequencyω and the superexchange coupling constantJ. We demonstratethe capability of Imχtotal + , − (ω, q) for plane copper 63(1/T1) and oxygen 17(1/T1) nuclear spin–lattice relaxation rate calculations from carrier free right up to optimally dopedLa2 − xSrxCuO4 and obtain the basic features of temperature and doping behavior for 63(1/T1) in agreement with experimental observations.